Calls a timer which starts from 00m:00s after certain time

Question

I am trying to make a start a timer clock MM:SS after a certain given interval on page.

I have tried setinterval function but the time it is showing resets after 3 seconds......i wanted it to be call the function only once so the internal function "TIMER CLOCK" keeps going on

setInterval(function timerx(){
var timer = setInterval(clock, 1000);
var msec = 00;
var sec = 00;
var min = 00;

function clock() {
    msec += 1;
    if (msec == 60) {
        sec += 1;
        msec = 00;
        if (sec == 60) {
            sec = 00;
            min += 1;
            if (sec % 2 == 0) {
                alert("Pair");
            }
        }
    }
    document.getElementById("timer").innerHTML = min + ":" + sec + ":" + msec;
}
}, 3000); //3000 value could be change 

Its like i have a certain amount of time suppose 5 minutes or 300 seconds

i want the timer to be started after 300 seconds and keep on going

Answer 1

Change the outer setInterval() to setTimeout(). The outer timeout only has run one time per your question. That is what setTimeout() is designed to do.